The aerosol fire-extinguishing technology, which occurred since the 1990s, is a technology that extinguishes fire by damaging the combustion chain reaction of free radicals in the flame through the chemical reaction of an activity inhibitor produced based on the vigorous oxidation-reduction reaction between oxidant and fuel. Owing to its characteristics such as non-toxicity, non-corrosivity, high capacity efficiency, long storage period, total flooding and all-round fire-suppressing, said technology has attracted much attention. Over ten years since the end of the last century, the aerosol technology has been rapidly developed with continuous emergence of relevant patents. The aerosol fire-extinguishing technology can be mainly divided into the three types: hot aerosol fire-extinguishing technology, cold aerosol fire-extinguishing technology and water mist fire-extinguishing technology. The hot aerosol fire-extinguishing technology includes pyrotechnic composition-based hot aerosol fire-extinguishing technology and water-based hot aerosol fire-extinguishing technology. At present, the pyrotechnic composition-based hot aerosol fire-extinguishing technology, for the most part, refers to pyrotechnic composition-based fire extinguishers that are based on a solid substance composed of an oxidant, a flammable agent, an adhesive and a combustion rate regulating agent. As a substitute for Halon, the pyrotechnic composition-based hot aerosol fire extinguisher displays a high fire-extinguishing efficiency, the fire-extinguishing apparatus is simply structured without the need to use any pressure-proof container, the fire-extinguishing components can be combined modularly, and stored at normal temperature and pressure, the maintenance is convenient, the fire extinguisher can be stored for a long period of time, and has a low cost, with an ozone depletion potential ODP=0, and a relatively low global warming potential GWP, thus is obviously superior than other types of fire extinguishers with respect to the price/performance ratio, which helps to open up the market and advance the implementation of the Halon substitute plan.
In the prior art before the disclosure of the present invention, an alkali metal nitrate, in particular potassium nitrate, is preferably selected by the pyrotechnic composition-based hot aerosol fire-extinguishing technology in most cases as an oxidant for pyrotechnic composition-based hot aerosol fire-extinguishers in consideration of its capability to satisfy most requirements in the principle of component selection. For the prior art using a single component potassium nitrate as oxidant in fire-extinguishing aerosol compositions, the most frequently used is the hot aerosol fire-extinguishing technology represented by Russian series patent groups, such as RU2230726, RU2184587, RU2214848, RU2150310, RU2108124, RU2091106, RU2076761, RU2151135, RU2116095, RU2006239, RU2022589, and also patents/patent applications in other countries/regions such as WO0158530, WO9733653, WO9423800, U.S. Pat. No. 5,831,209, U.S. Pat. No. 6,042,664, U.S. Pat. No. 6,264,772, U.S. Pat. No. 5,573,555, U.S. Pat. No. 6,116,348; secondly, there are fire-extinguishing aerosol compositions that adopt a dual-component or multi-component oxidant, in which the main component is potassium nitrate and/or potassium perchlorate and/or the auxiliary component is nitrates, carbonates of other alkali metals, alkaline earth metals, for example described in patents/patent applications CA2250325, DE19915352, UA7773, EP0561035, WO2005023370, RU2157271, RU2098156, US20020121622, U.S. Pat. No. 5,423,385, U.S. Pat. No. 5,492,180, U.S. Pat. No. 5,425,426 and U.S. Pat. No. 6,277,296. As to the selection of flammable agent, a wide range of substances can meet the principle of component selection. In general, those qualified organic or inorganic flammable agents are selected under the condition that the design of negative oxygen balance can be satisfied, e.g. the flammable agents disclosed in such patents/patent applications as RU218458, RU2214848, US20010011567, U.S. Pat. No. 6,264,772, RU2157271, RU2050878, U.S. Pat. No. 5,831,209, WO9733653 and EP0561035. As the water-based hot aerosol fire-extinguishing technology, the oxidant and flammable agent are mostly selected from such components as ammonium nitrate, ammonium perchlorate, potassium nitrate, strontium nitrate, guanidine nitrate and the like, which are capable of generating gas, moisture and metallic solid particles, with the proviso that the high-oxygen balance design is satisfied, according to the content as disclosed in patents/patent applications such as U.S. Pat. No. 6,277,296, U.S. Pat. No. 6,093,269, U.S. Pat. No. 6,045,726, U.S. Pat. No. 6,019,861 and U.S. Pat. No. 5,613,562.
The above hot aerosol fire-extinguishing technologies are all featured by high efficiency in fire suppression, low cost and convenient maintenance, thus are becoming a prosperous and popular product in recent years. However, many problems gradually occur in the above prior arts and products along with the marketization of actual products and deep development of research and manufacture. Lots of recent application practice and research have shown that during the use of potassium nitrate as a single oxidant or as the main component in a multi-component oxidant to achieve high-efficient fire suppression, the produced strong-alkaline electroconductive substance potassium hydroxide would also bring about a second damage to the protected space and object. For the water-based hot aerosol fire-extinguisher, in particular, it is easier to form an strong-alkaline electroconductive substance between the produced moisture and the metal oxide, which shall usually lead to such irreparable consequences as damage or corrosion of the electric equipments after the fire is quenched in the instrument room, control room, generator room, battery box, communication base station and electrical transformer station. Moreover, the produced nitrous oxide may produce neurotoxicity to human if it cannot be decomposed rapidly. In view of said situation, some research departments and manufacturers have come up with hot aerosol fire-extinguishing technical solutions that can give consideration to both the fire suppression efficiency and the second damage problem. For example, the patent application CN200510105449 discloses a technical solution with respect to aerosol fire-extinguishers using strontium nitrate as the only oxidant, in which the greatest problem is that the fire-extinguishing efficiency of the fire-extinguishers is greatly reduced even though the second damage to the precision electric appliance is lessened to a certain extent. In U.S. Pat. No. 5,613,562 and U.S. Pat. No. 5,609,210, the fire-extinguishing compositions employ strontium nitrate as oxidant, whose main effect is to function as a power source to gasify a second fire-extinguishing liquid containing a carbon-fluorine bond and a carbon-hydrogen-fluorine bond and then eject it to the fire, but the produced hydrofluoric acid is not only hypertoxic but also highly corrosive, belonging to the water-based hot aerosol technology. For the U.S. Pat. No. 6,019,861, although the fire-extinguishing composition also contains potassium nitrate and strontium nitrate, said components are only added as additives or auxiliary oxidants and are primarily used for improving the quality of dilatable gas, and the main oxidant is ammonium nitrate that has to be phase stabilized in said fire-extinguishing technology, although it is advantageous for a relatively low temperature, the combustion and gas generation rates are both affected. The U.S. Pat. No. 6,093,269 provides a high oxygen balance pyrotechnic gas generating composition, wherein a high concentration of strontium nitrate is required to maintain a neutral balance of oxygen/fuel, primarily used in propellant compositions for automobiles, gun propellers, expansion devices, air bags.
Prior arts CN1739820A, CN1150952C and CN1222331C relate to similar subject matters to the present invention, in which CN1150952C and CN1222331C are prior patent applications filed by the inventors of the present application, but have the following shortcoming: they fail to separately design fire extinguishers according to the insulation required by different electric equipments, in order to give consideration both to fire-extinguishing efficiency and corrosion to electric equipments. This is because different types of electric equipments may exhibit different holding capability to the decrease of insulation resistance caused by electrostatic accumulation or acid-base corrosion at different risks. For example, for such heavy-current electric devices as generator, motor, high- and low-pressure electric appliances, electric fence, electric cable and the like, the insulation resistance is generally required to be from ≧1 MΩ to <20 MΩ (see Serial Electric Power Industry Standards of the People's Republic of China, for example DL/T5161.7-2002, Specification for Construction Quality Checkout and Evaluation of Electric Equipment Installation (Quality Checkout of Electric Rotating Machine Construction), etc.); for such ordinary electric equipments as communication, computer, automotive electric equipment and medical electric equipment, the insulation resistance is generally required to be from ≧20 MΩ to <100 MΩ (see Electronics Industry Standards of the People's Republic of China series, Communication Industry Standards of the People's Republic of China series, Computer Industry Standards of the People's Republic of China series, such as GB6649-86 General Specification for Semiconductor Integrated Circuits, IPC 9201 Surface Insulation Resistance Handbook, etc.); for precision electric appliances composed of printed circuit board, base plate and the like, the insulation resistance is generally required to be ≧100 MΩ (see Electronics Industry Standards of the People's Republic of China series, Industry Standards for International Printed Circuits series and the like, such as IPC-CC-830B Handbook of Insulation Property and Quality of Printing Plate Assembled Appliances, GB 4793 Safety Requirements For Electronic Measuring Instruments, GJB 1717-93 General Specification for All-Purpose Printed Circuit Board Connectors, etc.). Since different electric equipments have different requirements for the insulation resistance, the use of the same formulated fire-extinguishing composition for said electric equipments may be improper in terms of both the fire-extinguishing efficiency and investment cost. Thus, the components in the compositions and the contents thereof designed in the applications including the prior patent applications of the present invention are far from perfect, and certain technical characteristic parameters need to be improved. In the prior art before disclosure of the present invention, apart from the above technologies, there does not exist any special technology regarding fire-extinguishing aerosol compositions that are suitable for precision electric appliances without reducing fire-extinguishing efficiency.